diff --git a/SRC/dlanv2.f b/SRC/dlanv2.f index c55b0ce510..9008fdde08 100644 --- a/SRC/dlanv2.f +++ b/SRC/dlanv2.f @@ -144,7 +144,7 @@ SUBROUTINE DLANV2( A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN ) * .. * .. Local Scalars .. DOUBLE PRECISION AA, BB, BCMAX, BCMIS, CC, CS1, DD, EPS, P, SAB, - $ SAC, SCALE, SIGMA, SN1, TAU, TEMP, Z, SAFMIN, + $ SAC, SCALE, SIGMA, SN1, TAU, TEMP, Z, SAFMIN, $ SAFMN2, SAFMX2 INTEGER COUNT * .. @@ -248,10 +248,14 @@ SUBROUTINE DLANV2( A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN ) * * Compute [ A B ] = [ CS SN ] [ AA BB ] * [ C D ] [-SN CS ] [ CC DD ] +* +* Note: Some of the multiplications are wrapped in parentheses to +* prevent compilers from using FMA instructions. See +* https://github.com/Reference-LAPACK/lapack/issues/1031. * A = AA*CS + CC*SN - B = BB*CS + DD*SN - C = -AA*SN + CC*CS + B = ( BB*CS ) + ( DD*SN ) + C = -( AA*SN ) + ( CC*CS ) D = -BB*SN + DD*CS * TEMP = HALF*( A+D ) diff --git a/SRC/slanv2.f b/SRC/slanv2.f index ac1a197822..40470867e7 100644 --- a/SRC/slanv2.f +++ b/SRC/slanv2.f @@ -144,7 +144,7 @@ SUBROUTINE SLANV2( A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN ) * .. * .. Local Scalars .. REAL AA, BB, BCMAX, BCMIS, CC, CS1, DD, EPS, P, SAB, - $ SAC, SCALE, SIGMA, SN1, TAU, TEMP, Z, SAFMIN, + $ SAC, SCALE, SIGMA, SN1, TAU, TEMP, Z, SAFMIN, $ SAFMN2, SAFMX2 INTEGER COUNT * .. @@ -248,10 +248,14 @@ SUBROUTINE SLANV2( A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN ) * * Compute [ A B ] = [ CS SN ] [ AA BB ] * [ C D ] [-SN CS ] [ CC DD ] +* +* Note: Some of the multiplications are wrapped in parentheses to +* prevent compilers from using FMA instructions. See +* https://github.com/Reference-LAPACK/lapack/issues/1031. * A = AA*CS + CC*SN - B = BB*CS + DD*SN - C = -AA*SN + CC*CS + B = ( BB*CS ) + ( DD*SN ) + C = -( AA*SN ) + ( CC*CS ) D = -BB*SN + DD*CS * TEMP = HALF*( A+D )