Exhibit 99.1

INVESTOR CONTACT:

Lisa L. Ewbank

Synopsys, Inc.

650-584-1901

Synopsys-ir@synopsys.com

EDITORIAL CONTACT:

Yvette Huygen

Synopsys, Inc.

650-584-4547

yvetteh@synopsys.com

Synopsys Posts Financial Results for Second Quarter Fiscal Year 2015

Q2 2015 Financial Highlights

MOUNTAIN VIEW, Calif. – May 20, 2015 – Synopsys, Inc. (Nasdaq: SNPS) today reported results for its second quarter of fiscal year 2015.

For the second quarter of fiscal year 2015, Synopsys reported revenue of $557.2 million, compared to $517.7 million for the second quarter of fiscal 2014, an increase of approximately 7.6 percent.

“Our fiscal second quarter results were very strong, and solidify our outlook for the full year,” said Aart de Geus, chairman and co-CEO of Synopsys. “We see clear momentum with our new implementation and verification products in the early stages of a multi-year customer upgrade cycle. Our entry into the software quality and security space has opened up an opportunity to drive incremental growth in both familiar and new market segments and build on Synopsys’ strengths.”

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GAAP Results

On a generally accepted accounting principles (GAAP) basis, net income for the second quarter of fiscal 2015 was $55.6 million, or $0.35 per share, compared to $63.3 million, or $0.40 per share, for the second quarter of fiscal 2014.

Non-GAAP Results

On a non-GAAP basis, net income for the second quarter of fiscal 2015 was $107.6 million, or $0.68 per share, compared to non-GAAP net income of $101.7 million, or $0.65 per share, for the second quarter of fiscal 2014. Reconciliation between GAAP and non-GAAP results is provided at the end of this press release.

Financial Targets

Synopsys also provided its financial targets for the third quarter and full fiscal year 2015. These targets do not include any impact of future acquisition-related activities or costs that may be incurred in fiscal year 2015. These targets constitute forward-looking statements and are based on current expectations. For a discussion of factors that could cause actual results to differ materially from these targets, see “Forward-Looking Statements” below.

Third Quarter of Fiscal Year 2015 Targets:

Full Fiscal Year 2015 Targets:

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GAAP Reconciliation

Synopsys continues to provide all information required in accordance with GAAP, but believes evaluating its ongoing operating results may not be as useful if an investor is limited to reviewing only GAAP financial measures. Accordingly, Synopsys presents non-GAAP financial measures in reporting its financial results to provide investors with an additional tool to evaluate Synopsys’ operating results in a manner that focuses on what Synopsys believes to be its ongoing business operations and what Synopsys uses to evaluate its ongoing operations and for internal planning and forecasting purposes. Synopsys’ management does not itself, nor does it suggest that investors should, consider such non-GAAP financial measures in isolation from, or as a substitute for, financial information prepared in accordance with GAAP. Synopsys’ management believes it is useful for itself and investors to review, as applicable, both GAAP information that includes: (i) the amortization of acquired intangible assets, (ii) the impact of stock compensation, (iii) acquisition-related costs, (iv) other significant items, including restructuring charges and certain accruals for legal and tax matters, and (v) the income tax effect of non-GAAP pre-tax adjustments as well as unusual or infrequent tax adjustments; and the non-GAAP measures that exclude such information in order to assess the performance of Synopsys’ business and for planning and forecasting in subsequent periods. Whenever Synopsys uses a non-GAAP financial measure, it provides a reconciliation of the non-GAAP financial measure to the most closely applicable GAAP financial measure. Investors are encouraged to review the related GAAP financial measures and the reconciliation of these non-GAAP financial measures to their most directly comparable GAAP financial measure as detailed below.

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Reconciliation of Second Quarter Fiscal Year 2015 Results

The following tables reconcile the specific items excluded from GAAP in the calculation of non-GAAP net income and earnings per share for the periods indicated below.

GAAP to Non-GAAP Reconciliation of Second Quarter Fiscal Year 2015 Results

(unaudited and in thousands, except per share amounts)

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Reconciliation of Target Non-GAAP Operating Results

The following tables reconcile the specific items excluded from GAAP in the calculation of target non-GAAP operating results for the periods indicated below.

GAAP to Non-GAAP Reconciliation of Third Quarter Fiscal Year 2015 Targets

(in thousands, except per share amounts)

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Earnings Call Open to Investors

Synopsys will hold a conference call for financial analysts and investors today at 2:00 p.m. Pacific Time. A live webcast of the call will be available at Synopsys’ corporate website at www.synopsys.com. A recording of the call will be available by calling +1-800-475-6701 (+1-320-365-3844 for international callers), access code 359327, beginning at 4:00 p.m. Pacific Time today. A webcast replay will also be available on the website from approximately 4:30 p.m. Pacific Time today through the time Synopsys announces its results for the third fiscal quarter in August 2015. Synopsys will post copies of the prepared remarks of Aart de Geus, chairman and co-chief executive officer, and Trac Pham, chief financial officer, on its website following the call. In addition, Synopsys makes additional information available in a financial supplement and corporate overview presentation, also posted on the corporate website.

Effectiveness of Information

The targets included in this release, the statements made during the earnings conference call and the information contained in the financial supplement and corporate overview presentation (available in the Investor Relations section of Synopsys’ website at www.synopsys.com) represent Synopsys’ expectations and beliefs as of the date of this release only. Although this press release, copies of the prepared remarks of the co-chief executive officer and chief financial officer made during the call, the financial supplement, and corporate overview presentation will remain available on Synopsys’ website through the date of the third quarter fiscal year 2015 earnings call in August 2015, their continued availability through such date does not mean that Synopsys is reaffirming or confirming their continued validity. Synopsys does not currently intend to report on its progress during the third quarter of fiscal year 2015 or comment to analysts or investors on, or otherwise update, the targets given in this earnings release.

Availability of Final Financial Statements

Synopsys will include final financial statements for the second quarter fiscal 2015 in its quarterly report on Form 10-Q to be filed by June 11, 2015.

About Synopsys

Synopsys, Inc. (Nasdaq:SNPS) is the Silicon to Software™ partner for innovative companies developing the electronic products and software applications we rely on every day. As the

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world’s 15th largest software company, Synopsys has a long history of being a global leader in electronic design automation (EDA) and semiconductor IP, and is also a leader in software quality and security testing with its Coverity^® solutions. Whether you’re a system-on-chip (SoC) designer creating advanced semiconductors, or a software developer writing applications that require the highest quality and security, Synopsys has the solutions needed to deliver innovative, high-quality, secure products. Learn more at www.synopsys.com.

Forward-Looking Statements

This press release and our upcoming earnings results conference call contain forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934. Any statements that are not statements of historical fact may be deemed to be forward-looking statements. Forward-looking statements include but are not limited to: sections of this press release entitled “Financial Targets” and “Reconciliation of Target Non-GAAP Operating Results”; and statements regarding Synopsys’ business, acquisitions (including the expected closing of our pending acquisition of Codenomicon OY), products, technologies, business model, new markets, customer demand for our technology, and projected financial results and business objectives. These statements involve known and unknown risks, uncertainties and other factors that could cause our actual results, time frames or achievements to differ materially from those expressed or implied in our forward-looking statements. Accordingly, we caution stockholders and prospective investors not to place undue reliance on these statements. Such risks, uncertainties and factors include, but are not limited to:

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In addition, Synopsys’ actual expenses, earnings per share and tax rate on a GAAP and non-GAAP basis for the fiscal quarter ending July 31, 2015; actual expenses, earnings per share, tax rate, and other projections on a GAAP and non-GAAP basis for fiscal year 2015; and cash flow from operations on a GAAP basis for fiscal year 2015 could differ materially from the targets stated under “Financial Targets” above for a number of reasons, including, but not limited to, (i) integration and other acquisition-related costs, (ii) application of the actual consolidated GAAP and non-GAAP tax rates for such periods, or judgment by management, based upon the status of pending audits and settlements, to increase or decrease an income tax asset or liability, (iii) a determination by Synopsys that any portion of its goodwill or intangible assets has become impaired, (iv) changes in the anticipated amount of employee stock-based compensation expense recognized in Synopsys’ financial statements, (v) actual change in the fair value of Synopsys’ non-qualified deferred compensation plan obligations, (vi) increases or decreases to estimated

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capital expenditures, (vii) changes driven by new accounting rules, regulations, interpretations or guidance, (viii) fluctuations in foreign currency exchange rates, (ix) litigation, (x) general economic conditions, and (xi) other risks as detailed in Synopsys’ SEC filings, including those described in the “Risk Factors” section in its Quarterly Report on Form 10-Q for the fiscal quarter ended January 31, 2015. Furthermore, Synopsys’ actual tax rates applied to income for the third quarter and fiscal year 2015 could differ from the targets given in this press release as a result of a number of factors, including the actual geographic mix of revenue during the quarter and year, and actions by the government. Finally, Synopsys’ targets for outstanding shares in the third quarter and fiscal year 2015 could differ from the targets given in this press release as a result of higher than expected employee stock plan issuances or stock option exercises, acquisitions, and the extent of Synopsys’ stock repurchase activity.

Synopsys is under no obligation to (and expressly disclaims any such obligation to) update or alter any of the forward-looking statements made in this earnings release, the conference call, the financial supplement, or the corporate overview presentation, whether as a result of new information, future events or otherwise, unless otherwise required by law.

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SYNOPSYS, INC.

Unaudited Consolidated Statements of Operations (1)

(in thousands, except per share amounts)

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SYNOPSYS, INC.

Unaudited Consolidated Balance Sheets (1)

(in thousands, except par value amounts)

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SYNOPSYS, INC.

Unaudited Consolidated Statements of Cash Flows (1)

(in thousands)

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